1. Field of the Invention
The present invention relates generally to spray formed rapid tools and, more specifically, to a method of making a spray formed rapid tool.
2. Description of the Related Art
It is known to make a spray formed rapid tool. In spray forming, a master model of a desired tool is produced using a free form fabrication technique. This master model is then used to create a ceramic pattern, which is the reverse of the desired tool to be produced. The resulting ceramic pattern is the receptor onto which metal is sprayed to form a deposit in the shape of the desired tool.
Typically, the spray forming process uses a wire-arc spraying. In wire-arc spraying, electric current is carried by two electrically conductive, consumable wires with an electric arc forming between the wire tips. A high-velocity gas jet blowing from behind the consumable wires strips away the molten metal, which continuously forms as the wires are melted by the electric arc. The high-velocity gas jet breaks up or atomizes the molten metal into finer particles in order to create a fine distribution of molten metal droplets. The atomizing gas then accelerates the droplets away from the wire tips to the ceramic pattern where the molten metal droplets impact the ceramic pattern to incrementally form a deposit in the shape of the desired tool. The completed desired tool is then mounted and used to produce parts in conventional stamping, die casting, or molding process.
Although the above process for making a spray formed rapid tool has worked well, it suffers from the disadvantage that chip making with heat-treating is required to make the spray formed rapid tool. These steps are both laborious and time consuming. Therefore, there is a need in the art to make a spray formed rapid tool that would eliminate these steps.
Accordingly, the present invention is a method of making a spray formed rapid tool. The method includes the steps of making a model of a desired tool and constructing a ceramic pattern as the inverse of the model. The method also includes the steps of heating the ceramic pattern and thermally spraying a metal material against the ceramic pattern to form the desired tool.
One advantage of the present invention is that a method is provided of making a spray formed rapid tool at the same time the spray material is being deposited. Another advantage of the present invention is that the method of making a spray formed rapid tool shortens product development cycle time. Yet another advantage of the present invention is that the method eliminates chip making with heat-treating when forming a spray formed rapid tool. Still another advantage of the present invention is that the method reduces material loss. Yet a further advantage of the present invention is that the method improves yield, quality, and repeatability.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.